Bank vs loose cubic yards

Three states of the same material

Earthwork is measured in whichever state the work is done in, and a single job touches all three. Excavation is paid in bank measure, because that is what the survey can see. Hauling is done in loose measure, because that is what fills the truck. Fill is placed and paid in compacted measure, because that is what the finished grade is made of.

• Bank (in place): undisturbed ground, measured from the survey. Written BCY.
• Loose: dug, broken and heaped — in the stockpile or the truck. Written LCY. Always more than bank.
• Compacted: placed and rolled. Written CCY. Usually less than bank, because compaction drives out air the natural ground still held.

The formulas

A worked example

Suppose the geotechnical report for a site gives 25% swell and 10% shrinkage for the material, and the survey shows 100 bank cubic yards to be dug. Those two percentages are the inputs to this example — chosen to make the arithmetic clear, not a statement about any particular soil.

The trucking is where this bites. Priced on the survey volume with 10-yard trucks, the haul looks like 10 loads. The trucks fill with loose material, so it is 125 ÷ 10 = 13 loads — 3 more trips than the bid allowed for, on a small job. The load factor of 0.80 says the same thing from the other side: each truck carries only 8 bank yards of the excavation.

Load factor by swell

Every row below is 1 ÷ (1 + swell), computed here rather than copied from a table. It is a conversion, not a property of any soil — which swell applies is the question the table cannot answer.

Where the factor comes from

Swell depends on the soil, its moisture, how it was dug and how it settles in the truck. Two materials with the same name can differ by more than the margin on the job. The honest sources, in order:

• The geotechnical report for the site, if there is one. It will state swell and shrinkage for the materials it identifies.
• Your hauler or excavator’s records for the same material from the same area — measured, not remembered.
• Measure it: a known bank volume, dug and loaded, against the loose volume it produced. One truck is enough to check a factor.
• A supplier’s ticket, for imported material — it will state loose density, which with the bank density gives the swell directly.

Generic tables give one number per soil name. This site publishes none and its calculators ship no default: a factor that is wrong by ten points changes the truck count by ten percent, and the table cannot tell you which way.

Which volume is on which invoice

The same job therefore has three different yard counts and all three are correct. The mistake is applying one of them to a line it does not belong to — most often pricing haul-off on the excavation volume.

How Calcumetryx handles it

The excavation calculator takes a swell percentage you enter and reports loose volume beside bank. The dirt hauling calculator takes the loose volume and your truck’s capacity and picks the limit that actually binds. The cut and fill calculator takes swell and shrinkage separately and reports whether cut material covers the fill once it has bulked and been compacted. None of them assumes a factor; each says what is missing when it is left blank.